Motility analysis within a gastrointestinal tract

ABSTRACT

A system and method for measuring and analyzing motility within a body lumen such as the gastrointestinal (GI) tract, where an in vivo imaging device such as a capsule captures images and transmits the images to a processor, which calculates the motility of the device based on comparison of the images. Preferably, the processor compares the intensity of pairs of images or of elements of pairs of images, generates a variance for the compared images, and calculates the motility of the imaging device from the variances. The motility data may be presented to a user in various manners; for example, a plot of motility over time may be generated, or indications of low motility may be presented to the user of the system.

The present application claims benefit from prior U.S. ProvisionalApplication Ser. No. 60/299,178 entitled “MOTILITY ANALYSIS WITHIN AGASTROINTESTINAL TRACT” filed on Jun. 20, 2001 and is a continuationInternational Application No. PCT/IL02/00386 entitled “MOTILITY ANALYSISWITHIN A GASTROINTESTINAL TRACT” filed on May 19, 2002.

FIELD OF THE INVENTION

The present invention relates to a method and system for analysis ofmotility within a body lumen, such as within the gastrointestinal (GI)tract.

BACKGROUND OF THE INVENTION

Normal peristalsis within a GI tract is responsible for transportingswallowed food and aiding in digestion and eventual evacuation.Peristalsis results in pressure waves moving along the GI tract, in turnresulting in the motility of a bolus within the GI tract. Thus, changesin motility along the GI tract may indicate normal conditions such asfood passing from one section of the GI tract to another (such aspassage from the stomach to the small intestine or passage from thesmall intestine to the large intestine). Certain pathological conditionscan alter the normal motility within the GI tract. Low motility may becaused by an obstruction or blockage or by other pathologicalconditions. It is often difficult to detect areas of low or abnormalmotility within the GI tract, since these areas may be in difficult toreach locations. It is difficult to “see” inside the tract, especiallyin sections that are hard to reach via conventional methods, such as thesmall intestines. Motility is the result of complex neuro-physiologicalprocesses. Motility disorders may be caused by nervous disorders, andmay not necessarily be visible as, for example, physiological changes inthe intestinal tissue.

Various in vivo measurement systems for examining a body lumen are knownin the art. A commonly known and used type of system is an endoscope.Endoscopes are devices which include a tube (either rigid or flexible)and an optical system, and which are introduced into the body to viewthe interior. The range of endoscopes—the portion of the GI tract, whichendoscopes are capable of viewing—is limited. Endoscopes are usually nothelpful in providing information on GI tract motility. Probes, such aspressure probes, may be used to measure peristaltic pressure waves.Other systems that may be used for obtaining information on GI tractmotility include dissolvable vehicles containing non dissolving markersthat are visible by X-ray. The vehicle is ingested and the progressionof the markers, which are released in the GI tract once the vehicle isdissolved, can be followed by X-ray. This method, however, can not beused for continuous monitoring and also exposes the patient to hazardousX-rays.

A non hazardous system and method for monitoring and/or analyzingmovement along the entire GI tract is needed, inter alia, forfacilitating the understanding of GI tract motility and for expandingdiagnostic (and perhaps therapeutic) possibilities in the GI tract.

SUMMARY OF THE INVENTION

An exemplary embodiment of the system and method of the presentinvention measures and analyzes motility within a body lumen such as theGI tract. In another embodiment of the invention a method is providedfor diagnosis of in vivo conditions in the GI tract of a patient. In oneembodiment an in vivo imaging device such as an ingestible imagingcapsule captures images and transmits the images to a processor, whichcalculates the motility of the device based on comparison of the images.In one embodiment the processor compares the intensity of pairs ofimages or of elements of pairs of images, generates an averagedifference for the compared images, and calculates the motility of theimaging device from the average differences. In other embodimentsindicators, such as radio frequency (RF) signals, strain gauges,velocity meters or accelerometers may be used to calculate the motilityof a device. In another embodiment a geometrical location or in vivoposition of the device may be determined for later calculation of themotility. The motility data may be presented to a user in variousmanners; for example, a plot of motility over time may be generated, orindications of low or abnormal motility may be presented to the user ofthe system.

According to an embodiment of the invention motility analysis data isexamined for at least one parameter, the parameter is compared to areference and at least one condition in the GI tract is deduced from thecomparison.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description taken in conjunction with thedrawings in which:

FIG. 1 is a schematic illustration of an in vivo imager system,according to one embodiment of the present invention;

FIGS. 2A and 2B show a simplified series of images, which may becaptured by the vivo imager system of FIG. 1;

FIG. 3 depicts a motility chart produced by the system of FIG. 1,according to one embodiment of the present invention;

FIG. 4 is a flow chart showing the steps for determining the motility ofa device recording images from a body lumen according to an exemplaryembodiment of the present invention; and

FIGS. 5A and 5B are histograms used to calculate motility according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, various aspects of the present inventionwill be described. For purposes of explanation, specific configurationsand details are set forth in order to provide a thorough understandingof the present invention. However, it will also be apparent to oneskilled in the art that the present invention may be practiced withoutthe specific details presented herein. Furthermore, well known featuresmay be omitted or simplified in order not to obscure the presentinvention.

The present invention relates to a method and system for analyzingmotility within a GI tract and for displaying motility to a user such asa health professional, who may use such data to, for example, diagnosepathologies. In an exemplary embodiment of the present invention, themotility of a capsule or other vehicle, which is propelled through theGI tract by the natural action of the GI tract is measured, giving anindication of the motility in the GI tract, in different portions of theGI tract. In one embodiment, the motility of the vehicle is calculatedvia an analysis of sequential images captured by the vehicle; thegreater the difference between sequential images, the greater themotility.

Reference is made to FIG. 1, which shows a schematic diagram of an invivo imaging system according to one embodiment of the presentinvention. In an exemplary embodiment, the system comprises a capsule 40having an imager 46, for capturing images, an illumination source 42,for illuminating the body lumen, and a transmitter 41, for transmittingimage and possibly other information to a receiving device. An opticalsystem (not shown), including, for example, lenses or mirrors, may aidin focusing reflected light onto the imager 46. The capsule 40 isswallowed by a patient and preferably traverses the patient's GI tract.In alternate embodiments the capsule 40 may have differentconfigurations and include other sets of components.

Preferably, while the capsule 40 traverses a patient's GI tract, thecapsule 40 transmits image and possibly other data to components locatedoutside the patient's body, which receive and process the data.Preferably, located outside the patient's body in one or more locations,are an image receiver 12, preferably including an antenna or antennaarray, an image receiver storage unit 16, a data processor 14, a dataprocessor storage unit 19, and an image monitor 18, for displaying,inter alia, the images recorded by the capsule 40 and motilityinformation. In one embodiment, the image receiver 12 and image receiverstorage unit 16 are small and portable, and are worn on the patient'sbody during recording of the images. Optionally, data processor 14, dataprocessor storage unit 19 and monitor 18 may be part of a personalcomputer or workstation, which includes standard components such asprocessor 14, a memory, a disk drive, and input-output devices, althoughalternate configurations are possible.

Data processor 14 may include any standard data processor, such as amicroprocessor, multiprocessor, accelerator board, or any other serialor parallel high performance data processor. Image monitor 18 may be acomputer screen or a conventional video display, but may, in addition,be a printer or any other device capable of providing an indication ofimage and/or position data.

Preferably, the imager 46 is a suitable CMOS camera, such as a “cameraon a chip” type CMOS imager specified by Given Imaging Ltd. of Israeland designed by Photobit Corporation of California, USA. In alternateembodiments, the imager 46 may be, for example, a CCD. The illuminationsource 42 may be, for example, a light emitting diode.

In operation, imager 46 captures images and sends data representing theimages to transmitter 41, which transmits images to image receiver 12using, for example, electromagnetic radio waves. Image receiver 12transfers the image data to image receiver storage unit 16. After acertain period of time of data collection, the image data stored instorage unit 16 is sent to data processor 14 or data processor storageunit 19. For example, the image receiver storage unit 16 may be takenoff the patient's body and connected to the personal computer orworkstation which includes the data processor 14 and data processorstorage unit 19 via a standard data link, e.g., a serial or parallelinterface of known construction. The image data is then transferred fromthe image receiver storage unit 16 to the data processor storage unit19. Data processor 14 analyzes the data and provides the analyzed datato the image monitor 18, where a health professional views, for example,the image data and motility information.

The image data collected and stored may be stored indefinitely,transferred to other locations, or manipulated or analyzed. A healthprofessional may use the images to diagnose pathological conditions ofthe GI tract, and, in addition, the system may provide information aboutthe location of these pathologies. While, using a system where the dataprocessor storage unit 19 first collects data and then transfers data tothe data processor 14, the image data is not viewed in real time, otherconfigurations allow for real time viewing. In such systems, imagemotility may be calculated and displayed in real time.

The image monitor 18 presents the image data, preferably in the form ofstill and moving pictures, and in addition may present otherinformation. In an exemplary embodiment, such additional information mayinclude, but is not limited to, absolute time elapsed for the currentimage being shown and the relative or absolute motility of the capsule40, over the course of the capsule's travel through the GI tract, and/orat the time corresponding to the current image being displayed. Absolutetime elapsed for the current image being shown may be, for example, theamount of time that elapsed between the moment the capsule 40 was firstactivated and the image receiver 12 started receiving transmissions fromthe capsule 40, and the moment that the current image being displayedwas captured. Various methods may be used to display the motility of thecapsule 40; such methods are discussed below. In an exemplaryembodiment, the various categories of information are displayed inwindows. Multiple monitors may be used to display image and other data.

Preferably, the image data recorded and transmitted by the capsule 40 isdigital color image data, although in alternate embodiments other imageformats may be used. In an exemplary embodiment, each frame of imagedata includes 256 rows of 256 pixels each, each pixel including data forcolor and brightness, according to known methods. For example, in eachpixel, color may be represented by a mosaic of four sub-pixels, eachsub-pixel corresponding to primaries such as red, green, or blue (whereone primary is represented twice). The brightness of the overall pixelis recorded by a one byte (i.e., 0-255) brightness value. Preferably,images are stored sequentially in data processor storage unit 19. Thestored data is comprised of one or more pixel properties, includingcolor and brightness.

While, preferably, information gathering, storage and processing isperformed by certain units, the system and method of the presentinvention may be practiced with alternate configurations. For example,components providing for motility analysis may be located inside acapsule or, alternately, on a portable device worn on the patient.Furthermore, the components gathering image information need not becontained in a capsule, but may be contained in any other vehiclesuitable for traversing a lumen in a human body, such as an endoscope,stent, catheter, needle, etc.

The in vivo imager system may collect a large volume of data, as thecapsule 40 may take several hours to traverse the GI tract, and mayrecord images at a rate of, for example, two images every second,resulting in the recordation of tens of thousands of images. The seriesof still images collected may later be presented as still images or as amoving image of the traverse of the GI tract. The image recordation rate(or frame capture rate) may be varied; for example, the imagerecordation rate may be varied based on capsule motility. While in theGI tract, the capsule 40 undergoes intermittent motion with longresidence time at some positions. These periods of long residence may benormal or can be due to pathologies, such as blockages, within thedigestive tract. The system and method of the present invention aidshealth professionals in monitoring the capsule motion and in diagnosingand locating, for example, areas of blockage. In addition, changes inmotility may be indicative of a normal condition such as the passage ofthe capsule 40 from one section of the GI tract to another, and thus thesystem and method of the present invention may use motility data todetermine the position of the capsule 40 or other diagnostic device.

In an exemplary embodiment, each image P_(i) in the data stream ofimages is compared to **its predecessor image P_(i−I) (or to otherprevious image P_(i−n)) to determine the motility of the capsule 40during the time between the capture of the two images. Various methodsof determining motility based on image comparison may be used. In anexemplary embodiment, the system and method analyze image similarity toobtain a measure of motility. It can be assumed that the more similartwo compared images are, the slower the movement of the capsule 40between the times the two images are captured. In an extremesituation—if the two compared images are identical—it can be assumed thecapsule 40 has not moved between the times the two images were captured.If two compared images differ greatly, it is an indication that thecapsule 40 was moving quickly between the times of capture of theimages. This concept is illustrated further in FIGS. 2A and 2B.

FIGS. 2A and 2B show a simplified series of images, which may becaptured by the vivo imager system of FIG. 1. Referring to FIGS. 2A and2B, a comparison of images provides information about the speed of thecapsule 40. In FIG. 2A, several consecutive images are shown in which aspecific point X is located in approximately the same location withineach of the images. In FIG. 2B, the same point X is located in varyingpositions within the images, taken over the same period of time. It canbe inferred that the images shown in FIG. 2A were taken by an imagerwhose position did not change by much between the times each image wastaken, and thus which had relatively low motility. It can be inferredthat the images shown in FIG. 2B were taken by an imager which is movingmore rapidly.

Preferably, data processor storage unit 19 stores a series of imagesrecorded by a capsule 40. The images may be combined consecutively toform a moving image of the images the capsule 40 recorded as it movedthrough a patient's GI tract. This moving image may be displayed in awindow on monitor 18. The moving image may be frozen to view one frame,speeded up, or reversed; sections may be skipped; or any other methodfor viewing an image may be applied to the moving image. While thefollowing discussion relates to the case where data from a capsule 40 isstored for later use, the system and method of the present invention maybe used with systems allowing for real time viewing of image data.

In an exemplary embodiment, to determine the motility of the capsule 40at various points during its journey through the GI tract, dataprocessor 14 first receives image data from data processor storage unit19. Data processor 14 then compares each image P_(i) in the data streamto its predecessor image P_(i−I) (or P_(i−n)) to determine the motilityof the capsule 40 during the time between the capture of the two images.

The comparison of images may be made on a pixel-by pixel basis or,alternatively, on a pixel cluster basis. In alternate embodiments,images may be compared without division into sections such as pixels orclusters. In an exemplary embodiment, the 256×256 pixel grid of eachimage is divided into a 32×32 grid of pixel clusters, to form 1,032clusters. In alternate embodiments, other methods of dividing an imagemay be used. Based on the comparison of the two images, data processor14 calculates the relative motility for the capsule 40 that captured theimages for the time period between the capture of the two images. In anexemplary embodiment, the resulting motility value at a certain point isa relative number on a certain scale, which indicates the motility ofthe capsule 40 relative to other points in the capsule's traverse of theGI tract. In alternate embodiments, absolute motility may be calculated.

The motility calculation is repeated for all or a set of images in theseries of images, and a series of motility values is generated. Theresulting motility values may be presented to the user in variousmanners. Preferably, the monitor 18 includes a window displaying animage frame or a moving image, a window showing the absolute timeelapsed in the image series for the frame being displayed (or thecurrent point in the moving image), and a window including a chart ofthe relative motility of the capsule 40 plotted against time. Anindication may be provided on the display on monitor 18 connectingcertain motility values, or regions having low motility or certainmotility patterns, to images or sections of the moving image. The usermay be able to indicate certain motility values or a portion of themotility chart or plot by, for example, clicking with a mouse, and havedisplayed the corresponding still or moving image.

Additional windows may display other data. For example, the position ofthe capsule 40 as it traverses the GI tract may be graphed as atwo-dimensional rendering of the three-dimensional path; such data maybe combined with or linked to image or motility data. Areas of lowmotility, or areas of altered or abnormal patterns of motility, may beindicated on such a capsule path representation by using, for example,color changes or labels.

In one embodiment, a spectral analysis of the motility data may beperformed, and the spectral analysis may be presented to the user or maybe used for diagnostic or other purposes. In a normal human GI tract,peristaltic waves are typically generated with some repetition. Aspectral analysis, according to known methods, of the peristaltic wavesof different time periods or sections of the series of motility data,may be performed and, for example, presented to the user. Such aspectral analysis may present, for example, the frequency of repetitionof peristaltic waves at different times or positions in a vehicle'stravel through the GI tract. In alternate embodiments, other visualindications of motility may be provided.

According to one embodiment of the invention, motility data can beexamined for at least one parameter or measurement that may be presentedas, for example, a specific pattern or representation of a pattern in aspectral analysis of the motility data or a specific repetition orrepresentation of a repetition of peristaltic waves. The parameter,possibly represented by a pattern or specific patterns, can be comparedto a reference, such as a parameter value in a normal or healthyindividual or a specific pattern typical of a pathological condition inthe GI tract. The comparison results can indicate, for example, aprevailing condition (or conditions) in the GI tract, thereby providinga diagnostic tool for identifying conditions in the GI tract. Forexample, a spectral analysis may be performed on the motility of anin-vivo device. The spectral analysis may be represented, for example,as a graph of movement waves over time; other ways of representing aspectral analysis may be used. A pattern matching module (for example,processor 14 operating according to software) may seek to match therecorded spectral analysis to spectral analyses corresponding to variousconditions, and a match or near match may be reported to a user.

FIG. 3 depicts a motility chart produced, for example, by the system ofFIG. 1, according to one embodiment of the present invention. The plotor chart 100 includes a time axis 102, a relative motility axis 104, anda motility plot or graphing 106. Preferably, if the health 20professional indicates a certain point along the motility chart, using,for example, a pointing device such as a mouse, the corresponding imageappears in the image window. While, in an exemplary embodiment, therelative motility is expressed in arbitrary units (for example, 0 to 10,adjusted logarithmically), other methods of expressing motility may beused, and absolute motility may also be expressed.

The chart 100 may include indications of low motility 108, which may be,for example, marks or colored or shaded regions indicating areas wheremotility is low enough to warrant investigation by a healthprofessional. The data processor 14 may filter for certain patterns ofmotility, where such patterns may commonly indicate either normalconditions, such as passage between areas of the GI tract, orpathological conditions. Such conditions may be labeled on the motilitychart. In response to such indications of low motility, the healthprofessional may click or otherwise indicate the area on the motilitychart in question, and view images (still or moving) of thecorresponding area in the GI tract.

Any number of methods may be used to analyze the image data to formmotility data. For example, motility analysis may be based on acalculation of the difference in a given property between correspondingpixels of two, not necessarily consecutive, frames; a calculation of thecross-correlation function between two, not necessarily consecutive,frames; a calculation of the changes of local statistical distributionsin two, not necessarily consecutive, frames; or a calculation of thechanges between corresponding local statistical distributions in two,not necessarily consecutive, frames. Local statistical distributions mayinclude, but are not limited to, the mean, the variance, or the standarddeviation of pixel clusters.

In an exemplary embodiment, each image in a pair of images beingcompared is divided into a number of sections. Each section in the firstimage is compared to the corresponding section in the second image. Thevariance of the difference of the brightness for the two sections,normalized by the number of sections, is calculated. The variance isused to ascertain the relative motility of the vehicle capturing images,which in an exemplary embodiment is capsule 40.

Reference is now made to FIG. 4, a flow chart showing the steps fordetermining the motility of a device recording images from a body lumenaccording to an exemplary embodiment of the present invention.

In step 200, image data is recorded by the capsule 40 and transmitted tothe data processor storage unit 19. In step 202, data processor 14receives from data processor storage unit 19 images P_(i) and P_(i+x),where x is usually, but not necessarily, 1. If the stream of images istoo lengthy or rapid, a decimation may be performed and non-adjacentimages may be compared, e.g., image P_(i) and P_(i+x), where x>1.

In step 204, data processor 14 may divide each of the two images intopixel clusters, sections or cells. In an exemplary embodiment, eachimage Pi is divided into 1024 clusters A_(i)(m,n), where 1<m<32 and1<n<32.

In step 206, data processor 14 calculates the average intensityI_(Ai(m,n)) of each cluster A_(i)(m,n) of each of image P_(i) andP_(i+x). Preferably, the intensity value for a cluster is the average ofthe brightness values for the pixels in the cluster. A matrix of theintensities of the clusters may be formed for each image. Alternatemethods of calculating intensity may be used; for example, color datamay be used to compare images.

In step 208, data processor 14 determines the absolute value D_(i)(m,n)of the difference of the average intensities I of A_(i)(m,n) andA_(i+x)(m,n) of corresponding clusters A(m,n) in the frames P_(i) andP_(i+x). D_(i)(m,n) is defined as:D _(i)(k,l)=|I_(A) _(i) _((k,l)) −I _(A) _(i+x) _((k,l))|A matrix of the absolute values of differences is formed, one valuebeing generated for each cluster compared.

In step 210, data processor 14 determines the average difference (Diff)between the two images. In an exemplary embodiment, the averagedifference is calculated by first subtracting from each absolute valuein the matrix created in step 208 the average value of all thedifferences in the matrix, summing the resulting values, taking thesquare root of the resulting sum, and dividing by the number of thedifferences in the matrix (in an exemplary embodiment 1024). This may beexpressed by the formula:${Diff} = {\sum\limits_{{m = 1},{32;{n = 1}},32}{{D_{i}\left( {m,n} \right)}/1024}}$where Diff corresponds to the average of the values in the differencematrix.

In an exemplary embodiment, the resulting average difference is a valuefrom 0 to U, where U is an arbitrary upper limit which depends upon theinput parameters. A low average difference indicates that the measuredvalue (in an exemplary embodiment, brightness) varies little between thecompared frames, and a high value of the average difference indicatesthat the measured value varies a large amount. A low difference is anindication of low motility, as, if the capsule 40 is not moving quickly,the images in the two compared frames will not vary by a large amount.

In step 212, if more frames exist in the image stream, data processor 14returns to step 202. If no more frames exist, data processor 14 proceedsto step 214. At this point, the difference data exists as a series ofdifference values, one for each frame pair analyzed, preferably X−1variances, where X is the number of frames analyzed.

In step 214, data processor 14 may normalize or decimate the resultingdifference data to an arbitrary scale. This normalized data representsthe relative motility of the capsule 40. In an exemplary embodiment,each difference datum, represented as a value from 0-U, is normalized toa number between 0 and 10; other ranges may be used. The normalizationprocess may be linear or may be non-linear—for example, a logarithmicfunction may be used. In alternate embodiments, other normalization ordecimation functions may be used; for example, the difference data maybe translated to a set of integers. During normalization, variousfunctions, such as logarithmic functions, may be applied to the data.

In step 216, data processor 14 provides an indication of motility forthe capsule 40. In an exemplary embodiment, data processor 14 creates aplot or graph of relative motility over time for display on the monitor18 using the normalized values created in step 214. Data processor 14may augment the graph with indications of low motility or indications ofcertain conditions. For example, sections of the graph where motilityfalls below a certain threshold may be marked in a certain color orpattern, or may be otherwise labeled.

In alternate embodiments, other methods of analyzing the image data toform motility data may be used. For example, for each frame pair, dataprocessor 14 may organize the difference values D_(i)(k,l) into a chart,for example, a histogram, as shown in FIGS. 5A and B. FIGS. 5A and Bdepict histograms used to calculate motility according to an embodimentof the present invention. Referring to FIGS. 5A and B, the absolutevalue D_(i)(m,n) of the difference is plotted on the x-axis of thehistograms and the number of corresponding pairs of cells, A_(i)(m,n)and A_(i+x)(m,n), which have a difference of magnitude D_(i)(k,l), isplotted on the y-axis. The histogram of in FIG. 5A represents ahistogram of cells in relatively similar frames, while the histogram ofFIG. 5B shows a histogram of cells in significantly different frames. Itshould be readily apparent that if two images are similar, the histogramof the differences in the cells of these images are concentrated at lowvalues of D_(i)(m,n). It should also be readily apparent that the centerof mass CM_(a) (the average difference between the two images) of thehistogram shown in FIG. 5A has a smaller value of D than the center ofmass CM_(b) of the histogram shown in FIG. 5B, and corresponds to aslower moving capsule 40. To calculate the difference between the twoframes, processor 14 determines the centers of mass CM of the histogramscorresponding to the two frames, and creates a difference value based onthe location of the CM. In another embodiment image analysis may be usedto determine the location of the capsule 40 in vivo (for example byidentifying image parameters that are typical to a specific region inthe GI tract) and the position information together with known factors;either the time that has elapsed during the translocation of the capsule40 or the velocity of the capsule 40 along its path, can be used tocalculate the motility. Similarly, the location of the capsule may bedetermined by other known methods and the location information can beused to calculate motility.

In alternate embodiments, methods of measuring motility may be usedwhich are not based on image analysis. For example, the capsule 40 mayinclude an accelerometer, which determines the instantaneousacceleration of capsule 40 as it moves through the GI tract. Anintegrator may convert the acceleration data to velocity data, and thisvelocity data may be used by the data processor to determine motility.Alternately, a pressure sensor or shear gauge attached to the capsule 40may detect peristaltic induced pressure or movement exerted by the wallsof the small intestine. The relationship between pressure and velocitymay be determined empirically, and then utilized to determine thevelocity or relative velocity of the capsule 40. A sensor in the capsule40 may detect movement relative to an artificially induced magneticfield, which is generated in the area of the patient's GI tract. Themagnetic field induces a current in a coil in the sensor, whosemagnitude is a function of the velocity of the coil through the field.Data on the induced current is converted to motility information.Further, external sensors may also be used, such as a Doppler ultrasoundunit, which continuously tracks the capsule 40. Additionally, thereceiver 12, which, according to one embodiment is adapted to receive RFsignals from the transmitter 41, may be used to monitor the intensity ofthe transmitted signal, whereas signals of unchanging intensitiesindicate that the transmitter 41 (and hence the capsule 40) is unmovingand signals of different intensities indicate that the transmitter 41 ismoving. One or more of the above methods, or other methods, may becombined to provide a determination of capsule motility.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the invention is defined bythe claims that follow:

1. A method for measuring and analyzing motility within a body lumen,the method comprising the steps of: accepting images acquired by avehicle disposed within said body lumen; and calculating a motility ofthe vehicle within said body lumen based on comparison of said acceptedimages.
 2. The method as in claim 1, wherein said vehicle is a capsule.3. The method as in claim 1, wherein said motility is relative motility.4. The method as in claim 1, wherein said motility is absolute motility.5. The method as in claim 1, wherein said comparison is a comparison ofimage intensity.
 6. The method as in claim 1, further comprising thesteps of: comparing two images; generating a variance for the twoimages; and repeating the comparing and variance generating steps for aplurality of image pairs to generate a series of variance values.
 7. Themethod as in claim 1, wherein the step of comparing the images includes,for a pair of images to be compared, at least the steps of: dividingeach image into sections; comparing corresponding sections of the imagesto produce a matrix of difference values; and calculating a variancebetween the two images, the variance based on a function of the matrix.8. The method as in claim 1 wherein said vehicle transmits image datafrom a gastrointestinal tract.
 9. The method as in claim 1, comprisingdisplaying an indication of motility.
 10. The method as in claim 1,comprising creating a plot which displays motility as a function oftime.
 11. The method as in claim 10, comprising: allowing a user toindicate a point on the plot; and displaying to the user a set of imagescorresponding to said point on the plot.
 12. The method as in claim 1,comprising the step of providing a visual indication of which of theimages correspond to a motility which is below a threshold.
 13. A systemfor measuring and analyzing motility within a body lumen, the systemcomprising: an image storage memory accepting images acquired by avehicle disposed within said body lumen; an image processor calculatinga motility of the vehicle within said body lumen based on comparison ofproperties of said accepted images; and a display on which a plot ofsaid motility as a function of time is displayed.
 14. The system as inclaim 13, wherein said vehicle is a swallowable vehicle.
 15. The systemas in claim 13, wherein said vehicle is a capsule.
 16. The system as inclaim 13, wherein said motility is relative motility.
 17. The system asin claim 13, wherein said motility is absolute motility.
 18. The systemas in claim 13, wherein said comparison is a comparison of imageintensity.
 19. The system as in claim 13, comprising a processorperforming the steps of: comparing two images; generating a variance forthe two images; and repeating the comparing and variance generatingsteps for a plurality of image pairs to generate a series of variancevalues.
 20. The system as in claim 13, wherein said vehicle includes atransmitter.
 21. The system as in claim 13, comprising: an input deviceaccepting an indication from a user of a point on the plot, wherein inresponse to said indication a set of images corresponding to said pointon the plot is displayed on said display.
 22. A system for measuring andanalyzing motility within a body lumen, the system comprising: an imagestorage means for accepting images acquired by an image capture meansdisposed within said body lumen; an image processor means forcalculating a motility of the image capture means within said body lumenbased on comparison of properties of said accepted images; and a displayon which a plot of said motility as a function of time is displayed. 23.The system as in claim 22, wherein said image capture means is disposedwithin a swallowable vehicle.
 24. The system as in claim 22, whereinsaid image capture means is disposed within a capsule.
 25. The system asin claim 22, wherein said motility is relative motility.
 26. The systemas in claim 22, wherein said motility is absolute motility.
 27. Thesystem as in claim 22, wherein said comparison is a comparison of imageintensity.
 28. The system as in claim 22, comprising a processing meansfor: comparing two images; generating a variance for the two images; andrepeating, for a plurality of image pairs, comparing and generating avariance, to generate a series of variance values.
 29. The system as inclaim 22, wherein said image capture means includes a transmittingmeans.
 30. The system as in claim 22, comprising: an input meansaccepting an indication from a user of a point on the plot; wherein inresponse to said indication a set of images corresponding to said pointon the plot is displayed on said display means.
 31. A method formeasuring and analyzing motility within a body lumen, the methodcomprising: accepting images acquired by a vehicle disposed within saidbody lumen; comparing two images; generating a variance for the twoimages; repeating the comparing and variance generating steps for aplurality of image pairs to generate a series of variance values;calculating a motility of said vehicle within said body lumen based onsaid series of variance values.
 32. A method for measuring and analyzingmotility within a body lumen, the method comprising: accepting imagesacquired by a capsule disposed within said body lumen; comparing pairsof said images; calculating a motility of said capsule within said bodylumen based on said comparisons; and creating a plot which displaysmotility as a function of time.
 33. A method for measuring and analyzingmotility within a body lumen, the method comprising: accepting imagesacquired by a vehicle disposed within said body lumen; comparing twoimages; generating a variance for the two images; repeating thecomparing and variance generating, steps for a plurality of image pairsto generate a series of variance values; calculating a motility of saidvehicle within said body lumen; and providing an indication of motility.34. A method for measuring and analyzing motility within a body lumen,the method comprising: accepting images acquired by a capsule disposedwithin said body lumen; comparing a set of images; generating a variancefor the set of images; repeating the comparing and variance generatingsteps to generate a series of variance values; calculating a motility ofsaid capsule within said body lumen; and providing an indication ofmotility of the capsule.
 35. A method for measuring and analyzingmotility within a body lumen, the method comprising: accepting imagesacquired by a capsule disposed within said body lumen; and calculating amotility of the capsule within said body lumen based on comparison ofsaid accepted images.
 36. A method for determining at least onecondition in a GI tract comprising the steps of: calculating a motilityof a device within the GI tract; creating a spectral analysis of saidmotility; examining the spectral analysis for at least one parameter;comparing said parameter to a reference; and determining a condition, ifany, in the GI tract based on the comparison.
 37. The method accordingto claim 36 further comprising creating a plot, which displays motilityas a function of time.
 38. The method according to claim 36 comprisingaccepting images acquired by the device.
 39. The method according toclaim 36 wherein calculating the motility includes at least comparingimages accepted from the device.
 40. The method according to claim 36wherein calculating the motility includes at least monitoring theintensity of RF signals transmitted from a capsule disposed within saidGI tract.
 41. The method according to claim 36, wherein said device is acapsule.
 42. A system for determining at least one condition in a GItract the system comprising: a receiver capable of receiving signalsfrom a device within the GI tract; and a controller capable of:calculating a motility of the device; creating a spectral analysis ofsaid motility; examining the spectral analysis for at least oneparameter; comparing said parameter to a reference; and determining acondition, if any, in the GI tract, based on the comparison.
 43. Thesystem according to claim 42 wherein the controller is capable ofcreating a plot which displays motility as a function of time.
 44. Thesystem according to claim 42 wherein calculating the motility includesat least comparing images accepted from the device.
 45. The systemaccording to claim 42 wherein said device is a capsule.